Thursday, 17 February 2011

It's time to try 20mph across the City

The case for a 20mph speed limit in the City of London is now so overwhelming, it is a win-win-win on social, environmental and economic grounds. It is literally costing the economy millions of pounds per year to keep the speed limit at 30mph. Despite this, the City decided in November 2010 that 'it would be preferable to exclude any reference to the City’s plans not to have a 20mph speed limit in the City' in the consultation on its new transport plan.

Safety – There has been no progress in reducing the toll of deaths and serious injuries in the last decade on the City's roads and it has the worst record in London if not the UK. Elsewhere in London, the reduction of the speed limit to 20mph has reduced collisions by as much as two-thirds. A temporary 20mph speed limit on Upper Thames Street, however, reduced collisions by an incredible 89% over three years. The City's strategy now is to try to improve safety by educating road users to be more careful. Given that this is a world financial centre with a high turnover of people, it's no surprise this strategy hasn't worked.

Besides the terrible emotional cost to friends, families and colleagues, there is an enormous economic cost. Based on Department for Transport figures for the cost of traffic collisions, the cost is over £20million per year. This figures are based on average incomes: in the City where most people are not just employed but on higher than average salaries, the cost of lost productivity is going to be more than double.

Congestion – Collisions are the biggest single cause of congestion, causing as much as 28% of delays, according to a Transport for London study made public in January 2011. While there is some predictability from delays caused by digging up the roads, congestion caused by blocked roads after collisions is not and this has a high economic cost due to the impacts on journey time reliability. Making it safer to walk and cycle would help reduce motor traffic levels and congestion further.

Air pollution – The City has some of the worst air pollution in Europe and is threatened with £300 million fines per year for breaching EU limits. By smoothing the traffic, eliminating unnecessary acceleration as well braking (tyre and brake wear now contribute to 37% of particulate pollution, according to the City's 2011 draft Air Quality Strategy), 20mph would have an immediate impact. Again, by encouraging walking and cycling over time, motor traffic levels would be reduced, reducing pollution levels further.

Noise pollution – Another problem in the City, this would likewise be reduced by avoiding the noise from unnecessary acceleration. Although the impact would vary depending on the time of day and traffic mix, a 20mph speed limit could reduce noise in some areas by 3dB, a noticeable difference.

Public opinion – The City's surveys of the public show that congestion is the biggest concern, followed by air pollution. Two-thirds of people want to improve conditions for cycling, a figure that has no doubt increased following the popularity of the cycle hire scheme, with even more wanting to improve conditions for walking. 20mph is a solution that is not just affordable and easy to implement but would have the greatest single impact for all these issues.

Journey times – The City's figures from 2003 show that drivers only exceed 20mph for a fifth of the time they spend driving in the City. Much of the time is spent stuck waiting at traffic signals. With a 20mph limit, traffic would flow at similar speeds, permitting the gaps between traffic signal phases to be shortened or the signals removed altogether at quieter junctions. There could actually be journey time improvements for drivers during the daytime.

Street clutter – Reducing the speed limit would allow the clutter of signs and lines to be reduced both in terms of sign size and amount of signage. The December 2009 DfT speed limit guidance allows much more flexibility to minimise signage clutter where 20mph is implemented. The few 20mph signs needed at the boundary of the 20mph zone could be merged with other signage, although with all but one of the City's neighbouring authorities implementing 20mph up to the City's boundary, in many instances there could be fewer 20mph signs rather than more.

Outlook

20mph could be introduced across the City in under a year for less than £500,000. By comparison the City plans to spend £130m over the next three years on transport. It's true that Transport for London (TfL) approval would be needed to cover the Bishopsgate A10 and Farringdon Street corridors, but TfL has already drawn up 20mph plans for the former and has a temporary 20mph on the latter. 20mph on the Upper Thames Street corridor, one of three places in Greater London that breaches EU pollution limits, would be more difficult as it is designated as part of the Olympic Route Network and would have to wait until late 2012.

For background, including details of a previous legal challenge that the City backed down from defending at the last minute, see this City Cyclists 20mph campaign page from 2004. In 2004 the City claimed it planned to implement subtle and effective traffic calming measures instead of 20mph. These measures have proved so subtle that, errr, no one has seen them.